Calcium Phosphate

Calcium phosphate is not one compound but a small family of calcium salts of orthophosphoric acid, and the grade decides the specification. Tribasic calcium phosphate, Ca3(PO4)2 (CAS 7758-87-4, molecular weight 310.18), carries the highest load at 38.8% theoretical elemental calcium and is the grade Thovek ships by default. Dibasic calcium phosphate, CaHPO4, supplies 29.5% calcium anhydrous (CAS 7757-93-9, MW 136.06) or 23.3% as the dihydrate (CAS 7789-77-7, MW 172.09), and is the workhorse of tablet formulation. Monobasic calcium phosphate, Ca(H2PO4)2 (CAS 7758-23-8, MW 234.05), sits lowest at 17.1% calcium but is acidic and water-reactive, which is what makes it useful as a leavening acid. All three carry the E341 additive numbers, (i) monobasic through (iii) tribasic. The formulation behaviour follows directly from solubility. Tribasic is effectively insoluble in water at roughly 1.2 mg/kg and dibasic at about 0.02 g/100 mL, so neither will cloud or destabilise a liquid the way a soluble mineral salt does, and both dissolve readily in dilute acid. That insolubility is an asset in dry systems: the light, bulky tribasic grade is a capable anticaking and free-flow agent in seasoning, powdered beverage and premix blends, while the denser dibasic grades compress cleanly and are used as tablet filler-binders as much as for the calcium they contribute. Monobasic grades find their place in bakery leavening systems and in acidulated dry mixes. Origin matters here commercially. Calcium phosphate can be manufactured from bone ash, which makes it unsuitable for vegan, vegetarian and several religious-certification programmes. Thovek supplies mineral-route material made from phosphate-rock-derived phosphoric acid and a calcium source, not bone, and states that on the Certificate of Analysis. The material is free from milk, egg, soy, fish, crustacean, gluten and nut allergens. Grades are available to USP/NF, Ph. Eur./BP and FCC/JECFA food specifications, with fluoride, lead, arsenic, cadmium and mercury tested per lot and particle size and bulk density cut to the buyer's specification.